The Bill & Melinda Gates Foundation spent billions of dollars exploring the idea that smaller high schools might result in higher graduation rates and better test scores. Instead, it found the key to better education is not necessarily smaller schools but more effective teachers.

Some people might cringe while recounting how much money the foundation spent figuring this out. But the foundation’s new CEO, Jeff Raikes, smiles and uses it as an example to explain that the world’s wealthiest charity has the money to try things that might fail.

"Almost by definition, good philanthropy means we’re going to have to do some risky things, some speculative things to try and see what works and what doesn’t," Raikes said May 27 during an interview with the Associated Press.

The foundation’s new "learner-in-chief" has spent the nine months since he was named CEO studying the operation, traveling around the world, and figuring out how to balance the pressures of the economic downturn with the growing needs of people in developing nations.

The former Microsoft Corp. executive, who turns 51 May 29, joined the foundation as its latest CEO after Patty Stonesifer, another former Microsoft executive, announced her retirement and his friends Bill and Melinda Gates talked Raikes out of retiring.

In the past decade, the foundation reportedly has given away nearly $20 billion, mostly in global health, global development, and U.S. education.

It has been ramping up its giving since Warren Buffett, head of Omaha, Neb.-based Berkshire Hathaway, announced in June 2006 that he would make annual donations of about $1.5 billion to the foundation, with the money to be distributed in the year it is donated.

Raikes is also from Nebraska, where he grew up on a family farm near Omaha. He and his wife, Tricia, formed the Raikes Foundation in 2002 to support youth development, education, and community issues in the Seattle area.

He hasn’t lost his easygoing manner, it is reported, during his transformation from business leader to nonprofit CEO.

One of the things he’s learned, he said, is the foundation must take a different direction with its education grants, and the best path is to support good, effective teachers.

Between 2000 and 2008, the foundation spent about $2 billion trying to improve America’s high schools and another $2 billion for scholarships, primarily for low-income and minority students.

It saw graduation rates go up in many foundation-supported schools. But it didn’t see significant improvements in student achievement or in the number of students who left high school ready to enroll in college.

Raikes said the responsibility for social innovation often falls on nonprofit organizations, because the private sector doesn’t see the profit margin in it and most citizens don’t want the government speculating with their tax dollars.

The foundation plans to continue to experiment with its education policy.

"We’re going to try some things, and I’m quite confident that some things will succeed and I’m quite confident that some things will fail," Raikes said.

He said half of the more than 1 million students who drop out of school in the United States each year are from just 100 school districts.

What can make a difference for those kids? Raikes wants to find out.

The foundation also is investing money to improve data collection in public schools–in part, to better find out what works–and to help community colleges improve graduation rates.

Raikes talked of a study of the Los Angeles Unified School District after an initiative to reduce class sizes led to a liberalization of rules on who could be hired to teach.

He said the district found that whether a teacher had a certificate had no effect on student achievement.

Raikes said the district found that putting a great teacher in a low-income school helped students advance a grade and a half in one year. An ineffective teacher in a high-income school held student achievement to about half a grade of progress in a year.

"We really have to focus classroom by classroom," said Jim Morris, chief of staff at the L.A. district. "Every teacher matters, just like every student matters."

Morris said the most important factor to successful schools is excellent teachers and supporting what they do in the classroom.

The Harvard researcher who studied the Los Angeles district, Thomas J. Kane, now works for the Gates Foundation as deputy director of education for data and research.